Die for attaching label to flexible article

ABSTRACT

A die for the attachment of a label to a flexible article, characterized by being provided with a label suction surface and the label suction surface having a regularly or irregularly jogging part formed in substantially the entire surface thereof and having suction holes disposed as enclosed with the protrusions of the jogging part. This die is capable of heating a label provided on one surface thereof with an adhesive surface formed by the application of a thermosensitive adhesive agent and attaching the heated label uniformly and tightly to the surface of the flexible article.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a die for the attachment of a label to thesurface of an article. More particularly, this invention relates to adie for heating a label provided on one surface thereof with an adhesivelayer and attaching the heated label uniformly and tightly to thesurface of a flexible article.

2. Description of the Prior Art

The flexible containers such as blood bags and transfusion bags bynature require attachment to their surface of a label displaying thekind, attributes, etc. of their contents. To date, the practice ofpreparing a pressure-sensitive label provided with an adhesive layercapable of exhibiting viscosity at normal room temperature and attachingthis pressure-sensitive label fast to such flexible articles as theflexible containers mentioned above has prevailed. Thepressure-sensitive label so attached to the surface has tended to peeloff spontaneously or to be readily peeled off intentionally because theadhesive force of the pressure-sensitive label of this nature isgenerally weak and the viscous force of the adhesive layer isdeteriorated by aging. When the label indicating the blood type (the ABOsystem, the pH system, etc.) and attached to the blood bag, for example,happens to be peeled off or intentionally or accidentally replaced byother label, there arises the possibility that incompatibility of bloodtype will occur at the time of transfusion and a serious accident suchas fatality on the part of a patient subjected to transfusion willensue. The use of the pressure-sensitive label of this nature,therefore, can not be called very adequate.

Recently, from this point of view, the method which comprises preparinga label provided on one surface thereof with an adhesive layer formed bythe application of a thermosensitive adhesive agent, heating the label,and applying the heated label to the surface of a flexible article hasbeen finding popular acceptance. Since the adhesive force due to thethermosensitive adhesive agent is strong at normal temperature and isdeteriorated only slightly by aging, the problem of the peeling of anattached label mentioned above does not occur so long as the label isthoroughly heated and attached uniformly to the surface of the flexiblearticle.

Heretofore, for the purpose of effecting continuous application of suchlabels to a plurality of flexible articles, it has been customary toprepare a die provided with a suction hole communicating with suctionmeans, keep a suction surface of the die heated as with a heater, causelabels to adhere tightly one after another to the heated suction surfaceand allow the thermosensitive adhesive agent on the labels to melt, andapply the label by pressure tightly to the surface of flexible articlesintended for application of label. Since the suction surface of the dieis flat and smooth, when the label which is thin and pliable is attachedby suction tightly to the suction surface, there ensues the possibilitythat a small amount of air is entrapped in the form of clusters of airbetween the suction surface and the label. In the portion of the labelunder which such clusters of air are formed as described above, theadhesion of the label to the suction surface is inferior because theclusters of air function as an insulating layer and consequently preventthe heat of the die from being amply transferred to the thermosensitiveadhesive agent. Moreover, since the surface of the flexible article suchas the blood bag which is intended for application of the label isliable to form a jogging contour particularly when the article is filledwith its content, the ambient air finds its way between the label andthe surface of the flexible article at the time that the label attachedtightly to the die is pressed against the flexible article. In theportion of the label under which the air is entrapped, the label isprevented from contacting the surface of the flexible surface andconsequently kept unattached thereto. When the portion of such inferiorattachment or no attachment occurs near the edge of the label, even thelabel using a thermosensitive adhesive agent has the possibility ofpeeling off the flexible article.

An object of this invention, therefore, is to provide a die for theattachment of a label to a flexible article, which die is improved so asto eliminate the problems heretofore encountered in the attachment of alabel to a surface as described above. This invention further concerns alabel-attaching die which is adapted to heat a label provided on onesurface thereof with an adhesive surface formed by the application of athermosensitive adhesive agent and attach the heated label uniformly andtightly to the surface of a flexible article. A further object of thisinvention is to provide a label-attaching die which is capable ofeffecting the attachment of a label so as to preclude the possibility ofthe attached label being peeled off the surface.

OBJECTS AND SUMMARY OF A PREFERRED EMBODIMENT OF THE INVENTION

The objects described above are accomplished by a label-attaching diefor attaching to a flexible article a label provided on one surfacethereof with an adhesive surface formed by the application of athermosensitive adhesive agent, which label-attaching die ischaracterized by being provided with a label suction surface and thelabel suction surface having a regularly or irregularly jogging partformed on the substantially entire surface thereof and having suctionholes disposed as enclosed with protruding points of the jogging part.

This invention further discloses a die for attaching a label to aflexible article, wherein the label suction surface has disposed thereindepressions having a width in the range of 0.5 to 2 mm and a depth ofnot less than 0.1 mm and spaced by an interval in the range of 1 to 5mm. This invention further discloses a die for attaching a label to aflexible article, wherein the label suction surface has depressionsdisposed latticewise therein. This invention further discloses a die forattaching a label to a flexible article, wherein the label suctionsurface has depressions disposed in an area accounting for 10 to 90% ofthe label suction surface, with the central part of the label suctionsurface as the center of the area.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a plan view illustrating a typical label attaching die for aflexible article as one embodiment of this invention, FIG. 1b is a crosssection taken through

FIG. 1a along the line A--A. FIG. 1c is a cross section taken throughFIG. 1a along the line B--B, FIG. 1d is a magnified plan view of thepart C of FIG. 1a, FIG. 1e is a magnified cross section of the part C ofFIG. 1a, FIG. 1f is a magnified plan view of the surface part of anothertypical label attaching die as another embodiment of this invention, andFIG. 1g is a magnified plan view of the surface part of the labelattaching die, FIGS. 2a and b are diagrams typically illustrating therelation existing between a label and a die when the label is attachedto a flexible article by the use of the label-attaching die of thepresent invention, FIGS. 3a and b are diagrams typically representingthe relation existing between a label and a flexible article when thelabel is attached to the flexible article by the use of thelabel-attaching die of this invention, FIG. 3c is a magnified view ofpart of FIG. 3b, FIGS. 4a and b are diagrams typically representing therelation existing between a label and a die when the label is attachedto a flexible article by the use of a conventional label-attaching die,and FIG. 5 is a diagram typically representing the relation existingbetween a label and a flexible article with the label is attached to theflexible article by the use of the conventional label-attaching die.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

A die 5 of this invention for the attachment of a label to a flexiblearticle, as illustrated in FIGS. 1a to 1e, is saliently characterized bybeing provided with a label suction surface and the label suctionsurface having a regularly or irregularly jogging part 3 formed on thesubstantially entire surface thereof and having suction holes 4 disposedas enclosed with protruding points of the jogging part 3.

To permit better comprehension of this invention, the problemencountered by the conventional label-attaching die will be describedbelow with reference to the accompanying drawings. A conventionallabel-attaching die 105 is provided with a flat and smooth label suctionsurface 106 as illustrated in FIGS. 4a and b. When a label is attachedto a flexible article by the use of this label-attaching die 105,therefore, the label 1 which is thin and pliable is readily bent at thetime that the label is attracted tightly to the label suction surface106 of the die 105 by drawing the ambient air in through the suctionholes 1 as illustrated in FIG. 4a. Consequently, while the label 1 istightly attached to the label suction surface 106 in the portions heldcontiguously with the suction holes 4 as illustrated in FIG. 4b, the airfinds its way between the label and the label suction surface 106 in theother portions and gives rise to clusters of air 7. Thus, there iscreated the state in which the label 2 is incapable of adhering tightlyto the label suction surface 106. In the portions of the label underwhich the clusters of air are formed, therefore, the clusters of airfunction as an insulating layer. Owing to this insulating layer, whenthe die 105 is heated, the heat is not sufficiently transferred to thelabel 2 and the thermosensitive adhesive agent on the adhesive layer 1is not melted. In the portions under discussion, therefore, inferioradhesion occurs between the label and the flexible article. Further,when the label 1 attracted tightly to the label suction surface 106 ofthe die 105 is pressed against the label-applying surface 9 of theflexible article the label-applying surface produces a slight joggingcontour because of the flexibility of the article. The air isconsequently entrapped between the label 1 and the label-applyingsurface 9 as illustrated in FIG. 5. The clusters of air 10 formed by theentrapped air inhibit the label 1 from adhering fast to thelabel-applying surface In the portions of the label under which theseclusters of air have been formed, therefore, inferior adhesion issuffered to occur.

In contrast, in the case of a label-attaching die 5 of this invention,even when the label 2 bends and the air finds its way between the labelsuction surface and the label 2 at the time that the label 2 isattracted tightly to the label suction surface of the die by drawing theambient air in through the suction holes 4 as illustrated in FIG. 2a,the air is dispersed in empty spaces as voids 11 formed by the joggingpart 3 imparted to the label suction surface 6 as illustrated in FIG. 2band consequently prevented from forming clusters of air. As the result,the label 2 is attached uniformly and tightly to the entirety of thelabel suction surface 6 and, owing to the heat applied to the die 5, thethermosensitive adhesive agent of the adhesive layer 1 of the label isthoroughly and uniformly melted throughout. Even when the label-applyingsurface 9 of the flexible article has a jogging contour and the air isentrapped between the label 2 and the label-applying surface asillustrated in FIG. 3a at the time that the label 2 attracted tightly tothe label suction surface 9 of the die is pressed against thelabel-applying surface of the flexible article 8, the label 2 is allowedto bend under the applied pressure in such a manner as to enter thedepressions 3a of the die 5 as illustrated in FIGS. 3b and 3c and theadhesive layer 1 of the label are caused to acquire a multiplicity ofuniform and minute depressions 12. Thus, the air is dispersed in thedepressions 12 and is prevented from forming clusters of air. As theresult, the label is attached uniformly and tightly to thelabel-applying surface 9 of the flexible article 8. Further, when themultiplicity of uniform and minute depressions 12 are formed asdescribed above in the adhesive layer 1 of the label, thethermosensitive adhesive agent present in the adhesive layer 1 of thelabel 2 in the portions in which the adhesive layer 1 contacts thelabel-applying surface of the flexible article 8 is caused by theapplied pressure to flow partly into the adjoining depressions 12. Asthe result, the thermosensitive adhesive agent layer at the portionsheld in contact with the label-applying surface of the flexible articlebecomes thinner and can be expected to manifest a distinctly increasedadhesive force.

Now, the present invention will be described more specifically belowwith reference to preferred embodiments.

The die 5 of this invention for the attachment of a label to a flexiblecontainer, as illustrated in FIGS. 1a to 1e, is provided with a labelsuction surface 6. This label suction surface has a regularly orirregularly jogging part formed substantially on the entire surfacethereof and have suction holes disposed as enclosed with theprotuberances 3a of the jogging part 3.

On the label suction surface of the die the jogging part 3 is formedsubstantially throughout the entire surface thereof as illustrated inFIGS. 1d and 1e. The jogging part 3 comprises recesses formed in anydesired pattern on the label suction surface 6. It may be obtained, forexample by shaping the depressions 3a in lines, lattices, dots, etc.Preferably, the jogging part is formed so that the depressions 3a may bedisposed latticewise as illustrated in FIG. 1a and FIGS. 1d and 1e.Though the jogging part 3 may be patterned regularly or irregularly, itis desired to be formed regularly. The depressions 3a of the joggingpart 3 are desired to have a width in the range of 0.5 to 2 mm,preferably 0.5 to 1.0 mm, and a depth of not less than 0.1 mm,preferably not less than 0.5 mm, and to be spaced by an interval in therange of 1 to 5 mm, preferably 2 to 3 mm. Further, the depressions 3aare desired to be disposed in an area accounting for 10 to 90%,preferably 40 to 70%, of the label suction surface, with the centralpart of the label suction surface 6 of the die 5 as the center thereof.

In the label suction surface of the die a plurality of suction holes 4are performed as enclosed with the projections 3b of the jogging partThese suction holed 4 communicate with a cavity 13 formed inside the die5. The cavity 13 is intended to communicate with suction means at thetime that the die 5 is set in place in a press. In FIGS. 1a to e, thesuction holes 4 are depicted as being disposed in the protuberances ofthe jogging part 3. They may be otherwise disposed in the depressions 3aof the jogging part 3 as illustrated in FIGS. 1f and g so long as theyare enclosed with the protuberances 3b. The die 5 in the presentembodiment is further provided with a heater insertion hole 14 for theinsertion of a heater as heating means and with a thermometer insertionhole 15 for the insertion of a thermometer (thermocouple).

The application of a label to a flexible article by the use of thelabel-attaching die which is constructed as described above isaccomplished as follows.

First, the cavity 13 of the die is caused to communicate with a suctiondevice (not shown) and a heater is set in place in the heater insertionhole 14 of the die

In the die of the present embodiment, the heater inserted in the heaterinsertion hole 14 is utilized as heating means. Of course, the heatingmeans need not be limited to this heater but may be any device which isrequired only to be capable of heating the label suction surface 6 ofthe die to a desired temperature. Further a thermocouple is inserted inthe thermometer insertion hole 15 of the die 5.

After these necessary devices have been set in place in the die 5 asdescribed above, the label suction surface 6 of the die 5 is broughtinto tight contact with the label. This label 2 is provided with anadhesive layer produced by application of a thermosensitive adhesiveagent using an ethylene-vinyl acetate copolymer, polyethylene,polypropylene, an ethylene-ethyl acrylate copolymer, a polyamide, or apolyester as a principal component thereof. When the suction devicementioned above is actuated while the label suction surface 6 of the die5 is held in tight contact with the label 2, the label 2 is attachedfast to the label suction surface as the suction holes 4 communicatingwith the cavity 13 simultaneously attracts the label 2 and draw in theambient air.

Since the label suction surface 6 of the die 5 is provided substantiallyon the entire surface thereof with the jogging part as described above,the air which possibly finds its way between the label suction surface 6and the label 1 is dispersed into the empty spaces formed by the joggingpart 3. Thus, the label 2 is attached uniformly and tightly to the labelsuction surface 6.

Now, the die 5 keeping the label 2 attached tightly thereto is set onthe label-applying surface of the flexible article so as to press thelabel 2 against the label-applying surface When the flexible article 8to which the label 2 is attached is a flexible container such as, forexample, a blood bag or a transfusion bag, the attachment of the labelmay be carried out while the container is filled with its content orwhile the container is not filled with the content. Even when thecontainer is filled with its content and the label-applying surface 9thereof is liable to produce a contour, the air possibly entrappedbetween the label 2 and the label-applying surface as described above isdispersed in the multiplicity of uniform and minute depressions 12 onthe adhesive layer 1 of the label to be formed by the depressions 3a ofthe die 5. Thus, the label 2 is allowed to adhere uniformly and tightlyto the flexible article.

In this case, since the label suction surface 6 of the die has beenalready heated to a temperature in the neighborhood of 140°35° C. to145°2° C. by the heater placed inside the heater insertion hole 14, thethermosensitive adhesive agent of the adhesive layer 1 of the label 2 ismelted by this heat and allowed to adhere fast to the flexible article8.

Thereafter, the suction of the label by the suction means is stopped andthe label-applying surface 6 of the die 5 is moved away the flexiblearticle 8 to discontinue the pressed contact and complete the attachmentof the label. The thermosensitive adhesive agent applied fast in amolten state to the flexible article is gradually cooled and solidifiedin the air to fasten the label with high adhesiveness to the flexiblearticle 8.

The label once applied to the flexible article by the use of thelabel-attaching die of this invention does not peel off the flexiblearticle because the adhesive agent is a thermosensitive substance. Thethermosensitive label which is thus destined to acquire a tamperproof(sealing) function, therefore, can be attached with high uniformity andadhesiveness to the surface of the flexible article as described above.The die of this invention accordingly, contributes very advantageouslyto the attachment of a label to a flexible article, particularly to aflexible medical container such as, for example, a blood bag or atransfusion bag.

Now, the present invention will be described more specifically belowwith reference to working examples.

EXAMPLE

As a die for incorporation in a heating type press, a die provided witha label suction surface 95×95 mm in area and having grooves 0.8 mm inwidth and 1 mm in depth disposed latticewise on the label suctionsurface in an area of 70×70 mm, with the central part of the labelsuction surface as the center thereof was used. When labels are attachedcontinuously to flexible containers one after another by the use of thisdie, the percent defective was as low as less than 0.1%.

Control

Continuous attachment of labels to flexible containers was carried outby following the procedure of the example described above, excepting adie provided with a flat smooth label suction surface 95×95 mm in areawas used as a die for incorporation of a heating type press. In thiscase, the percent defective was on the order of 2 to 3%.

From the results described above, it is clearly noted that the use ofthe label-attaching die of this invention brought about a notabledecrease in the percent defective in the attachment of labels.

Economic Utility of the Invention

As described above, this invention is directed to a label-attaching dieprovided on one surface thereof with an adhesive layer produced byapplication of a thermosensitive adhesive agent and used for theattachment of a label to a flexible article, which label-attaching dieis characterized by being provided with a label suction surface and thelabel suction surface having a regular or irregular jogging part formedsubstantially throughout the entire surface thereof and suction holesdisposed as enclosed with the protuberances of the jogging part. Evenwhen the air is suffered to find its way between the label and thelabel-applying surface of the flexible container at the time that thelabel is attached to the flexible article by the use of this die, thejogging contour imparted to the label suction surface of the diefunctions to dispersed the air and consequently create a statesubstantially free from clusters of air. Thus, the label can be attachedwith high uniformity and adhesiveness to the surface of the flexiblearticle. Further, since the attachment of the label is attained with thethermosensitive adhesive agent, the adhesive force is so strong as topreclude the possibility of the attached label peeling off the surfaceof the flexible article. For the attachment of a label to a flexiblearticle for which the accidental or intentional separation of theattached label entails a serious problem as in the case of a medicalcontainer such as, for example, a blood bag or a transfusion bag, thedie of this invention is used ideally. The attachment of a label to aflexible article is attained with enhanced uniformity and tightness whenthe die of this invention is provided on the label suction surfacethereof with depressions 0.5 to 2 mm in width and not less than 0.1 mmin depth disposed in an area accounting for 10 to 90% of the labelsuction surface, with the central part of the label suction surface asthe center thereof.

What is claimed is:
 1. A label-attaching die for attaching to a flexiblearticle a pliable label having a layer of thermosetting adhesive on aside thereof which is to be applied against the article, saidlabel-attaching die being heated and provided with a label suctionsurface for gripping a non-adhesive side of the label, said suctionsurface including a jogging section with suction holes operativelyconnected to a suction means, said suction holes being disposed in saidjogging section for admitting suction from said suction means whichremoves a portion of the air from between the label and the joggingsection and which sucks the non-adhesive side of the label against aidsuction surface, said jogging section including recesses situatedbetween said suction holes, said recesses defining voids for receivingportions of the label pushed therein by air trapped between the labeland the article.
 2. A label-attaching die according to claim 1, whereinsaid recesses have a width in the range of 0.5 to 2 mm and a depth ofnot less than 0.1 mm and being spaced by an interval in the range of 1to 5 mm.
 3. A label-attaching die according to claim 1, wherein saidrecesses are disposed in an area accounting for ten to ninety percent ofsaid label suction surface.
 4. A label-attaching die according to claim1, wherein said recesses are disposed in an area accounting for forty toseventy percent of said suction surface.
 5. A label-attaching dieaccording to claim 1, wherein said recesses are formed by intersectinggrooves.
 6. A label-attaching die according to claim 5, wherein saidsuction surface includes peripheral edges, said intersecting groovesterminating short of said edges.
 7. A label-attaching die according toclaim 1, wherein said jogging section is surrounded by another portionof said suction surface which is free of said suction holes andrecesses.
 8. Apparatus for attaching to an article a pliable labelhaving a layer of thermosetting adhesive on a side thereof which is tobe applied against the article, said apparatus comprising supportingmeans for supporting an article, and a die disposed opposite saidsupporting means for carrying the label which is attached to the articlewhen the die and article are pressed together, said die comprising asuction surface for gripping a non-adhesive side of the label, saidlabel suction surface including suction holes operatively connected to asuction means for admitting suction which removes a portion of the airfrom between the label and the jogging section and which sucks thenon-adhesive side of the label against said suction surface, means forheating said die whereby heat is transferred through said suctionsurface to the label, said suction surface including recesses situatedbetween said suction holes, said recesses defining voids for receivingthe remaining portion of air trapped between said suction surface andthe label, and for receiving portions of the pliable label pushedthereinto by air trapped between the label and article.
 9. A method ofattaching to an article a pliable label having a layer of thermosettingadhesive on a side thereof which is to be applied to the article, saidmethod utilizing a die having a suction surface with suction holestherein and recessses disposed between said suction holes defining voidsin said suction surface, said method comprising the steps of: heatingsaid die and admitting suction through said suction holes to suck anon-adhesive side of the label against suction surface, whereby airtrapped between said suction surface and the label enters said voids;and pressing the die against the article, whereby air trapped betweenthe label and the article pushes portions of the pliable label into saidvoids.